.\" Copyright (c) 2011 Kai Wang
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.\" $Id: dwarf_lineno.3 3640 2018-10-14 14:09:13Z jkoshy $
.\"
.Dd February 5, 2011
.Dt DWARF_LINENO 3
.Os
.Sh NAME
.Nm dwarf_lineaddr ,
.Nm dwarf_linebeginstatement ,
.Nm dwarf_lineblock ,
.Nm dwarf_lineendsequence ,
.Nm dwarf_lineno ,
.Nm dwarf_lineoff ,
.Nm dwarf_linesrc ,
.Nm dwarf_line_srcfileno
.Nd retrieve information associated with a DWARF line descriptor
.Sh LIBRARY
.Lb libdwarf
.Sh SYNOPSIS
.In libdwarf.h
.Ft int
.Fo dwarf_lineaddr
.Fa "Dwarf_Line ln"
.Fa "Dwarf_Addr *ret"
.Fa "Dwarf_Error *err"
.Fc
.Ft int
.Fo dwarf_linebeginstatement
.Fa "Dwarf_Line ln"
.Fa "Dwarf_Bool *ret"
.Fa "Dwarf_Error *err"
.Fc
.Ft int
.Fo dwarf_lineblock
.Fa "Dwarf_Line ln"
.Fa "Dwarf_Bool *ret"
.Fa "Dwarf_Error *err"
.Fc
.Ft int
.Fo dwarf_lineendsequence
.Fa "Dwarf_Line ln"
.Fa "Dwarf_Bool *ret"
.Fa "Dwarf_Error *err"
.Fc
.Ft int
.Fo dwarf_lineno
.Fa "Dwarf_Line ln"
.Fa "Dwarf_Unsigned *ret"
.Fa "Dwarf_Error *err"
.Fc
.Ft int
.Fo dwarf_lineoff
.Fa "Dwarf_Line ln"
.Fa "Dwarf_Signed *ret"
.Fa "Dwarf_Error *err"
.Fc
.Ft int
.Fo dwarf_linesrc
.Fa "Dwarf_Line ln"
.Fa "char **ret"
.Fa "Dwarf_Error *err"
.Fc
.Ft int
.Fo dwarf_line_srcfileno
.Fa "Dwarf_Line ln"
.Fa "Dwarf_Unsigned *ret"
.Fa "Dwarf_Error *err"
.Fc
.Sh DESCRIPTION
These functions retrieve specific line information associated with
the line descriptor specified by argument
.Ar ln ,
and stores it in the location pointed to by argument
.Ar ret .
If argument
.Ar err
is not NULL, it will be used to store error information in case of an
error.
.Pp
Function
.Fn dwarf_lineaddr
stores the program address corresponding to the source line specified
in argument
.Ar ln
into the location pointed to by argument
.Ar ret .
.Pp
Function
.Fn dwarf_linebeginstatement
sets the location pointed to by argument
.Ar ret
to 1 if the source line specified by the line descriptor
.Ar ln
is the beginning of a statement, or to 0 otherwise.
.Pp
Function
.Fn dwarf_lineblock
sets the location pointed to by argument
.Ar ret
to 1 if the source line specified by the line descriptor
.Ar ln
is the beginning of a basic block, or to 0 otherwise.
.Pp
Function
.Fn dwarf_lineendsequence
sets the location pointed to by argument
.Ar ret
to 1 if the program address associated with the line descriptor
.Ar ln
is the address immediately following the end of a sequence of target
machine instructions, or to 0 otherwise.
.Pp
Function
.Fn dwarf_lineno
stores the line number of the source line associated with the line
descriptor
.Ar ln
into the location pointed to by argument
.Ar ret .
.Pp
Function
.Fn dwarf_lineoff
stores the column number within a line associated with descriptor
.Ar ln
into the location pointed to by argument
.Ar ret .
The retrieved column numbers are 1-based, with the value -1 indicating
that column number information was not available.
.Pp
Function
.Fn dwarf_linesrc
stores a pointer to a NUL-terminated string containing the source file
name associated with line descriptor
.Ar ln
into the location pointed to by argument
.Ar ret .
The full path of the source file is returned if possible.
The memory used for the source file name string is managed by the DWARF(3)
library and should not be directly freed by application code.
Instead, portable code should use
.Xr dwarf_dealloc 3
to indicate that the string should be freed.
.Pp
Function
.Fn dwarf_line_srcfileno
stores the index of the source file associated with the line descriptor
.Ar ln
in the location pointed to by argument
.Ar ret .
The returned value is 1-based index into the array of source file
names returned by
.Xr dwarf_srcfiles 3 .
.Sh RETURN VALUES
On success, these functions returns
.Dv DW_DLV_OK .
In case of an error, they return
.Dv DW_DLV_ERROR
and set the argument
.Ar err .
.Sh ERRORS
These functions may fail with the following errors:
.Bl -tag -width ".Bq Er DW_DLE_LINE_FILE_NUM_BAD"
.It Bq Er DW_DLE_ARGUMENT
Either of the arguments
.Va ln
or
.Va ret
was NULL.
.It Bq Er DW_DLE_LINE_FILE_NUM_BAD
The source file name associated with the line descriptor
.Ar ln
could not be retrieved by function
.Fn dwarf_linesrc .
.El
.Sh SEE ALSO
.Xr dwarf 3 ,
.Xr dwarf_dealloc 3 ,
.Xr dwarf_srcfiles 3 ,
.Xr dwarf_srclines 3
